问Rails 3 before_filter设置和检查布尔值？？纸质追逐/寻宝游戏

EN

 t.integer :qr_code

def add_qr
  user = User.find_by_id(params[:id])
  if user.qr_code != params[:qr_code]-1
    redirect_to(some_url)
  else
    user.qr_code+=1
    user.save
    #do whatever else you need to do and display view
  end
end

def add_code(qr)
    # Check that qr immediately follows self.last_qr;
    # if it does, then update and save things and
    # continue on; if it doesn't, then raise an
    # exception that says, more or less, "QR Code out
    # of sequence".
end

before_create :initialize_qrs
validate :contiguous_qrs

#...

def initialize_qrs
  self.last_qr   = 0
  self.latest_qr = 0
end

def contiguous_qrs
  if(self.last_qr == 0 && self.latest_qr == 0)
    # New user, no worries.
    true
  elsif(self.latest_qr != self.last_qr + 1)
    # Sequence error, your `add_code` method should
    # prevent this from ever happening but, hey, bugs
    # happen and your code shouldn't trust itself any
    # more than it has to.
    false
  end
  true
end

def enter_code
    # Get the code and validate it, leave it in qr
    begin
      current_user.add_code(qr)
    rescue Exception => e
      # Complain and wag your finger at them for cheating
    end
    # Give them instructions for finding the next one,
    # these instructions would, presumably, come from
    # something like "instructions = qr.next_one.instructions".
end

create table "user_qr_codes" do |t|
  t.datetime "created_at", :null => false
  t.datetime "updated_at", :null => false
  t.integer  "user_id",    :null => false
  t.integer  "qr_code_id", :null => false
end